Search

The dissociative chemisorption of oxygen on Ir(110) has been investigated using supersonic molecular beam techniques. The initial probability of dissociative chemisorption (in the limit of zero surface coverage) as a function of incident kinetic energy between 1 and 28 kcal/mol and surface temperature from 85 to 1000 K is reported. For beam kinetic energies less than approximately 4 kcal/mol, the measured values of the initial probability of dissociative chemisorption are explained by a trapping-mediated adsorption mechanism. In this adsorption regime initial probabilities of dissociative chemisorption decrease with both increasing beam energy and surface temperature. The trapping probability of oxygen into the physically adsorbed state on Ir(110) as a function of incident beam energy is presented. For beam kinetic energies greater than ∼4 kcal/mol, a direct chemisorption mechanism dominates. In the direct adsorption regime, initial probabilities of dissociative chemisorption increase with increasing beam energy, and they are dependent on surface temperature, with the dependence decreasing with increasing surface temperature. This behavior is attributed to direct chemisorption into a molecularly chemisorbed state, from which there is a thermally activated kinetic competition between desorption and dissociation. A pseudo-steady-state kinetic model including physically adsorbed oxygen, molecularly chemisorbed oxygen, and atomically chemisorbed oxygen is applied to find that the activation barrier to desorption from the physically adsorbed molecular state is 1.6±0.1 kcal/mol higher than the barrier to conversion to the molecularly chemisorbed state. The activation barrier for desorption from the molecularly chemisorbed state is 1.5±0.15 kcal/mol greater than the barrier to dissociation from this state. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates repulsive interactions of potassium in rhenium using temperature programmed desorption, work-function measurements and optical second-harmonic generation. Evaluation of the validity of available electrostatic models for explaining simultaneously both sets of data; Activation energy for desorption in the limit of zero coverage.

Presents a study which examined the strength of rare-earth and transition-metal exchange coupling in R[sub2]iron[sub14]boride compounds. Experimental details; Results and discussion; Conclusions.

Presents a study which examined the crystallographic and magnetic properties of the compounds Ho2iron[sub14-x]manganese[subx]carbon. Experimental details; Results and discussion; Conclusions.

Presents a study that examined high-field magnetization in coupled holmium and cobalt magnetic sublattice. Methodology; Determination of the spontaneous magnetization of the compound; Evaluation of the hysteresis in the magnetization curves.

The article reports on results of a study of the modulation of fibroblast behaviour by enzymatically-tailored pectins. A description of the experimental set-up and measurement method is presented. The study concluded that grafted-engineered pectins modulate fibroblast adhesion through serum adhesive protein adsorption/conformation.

Over the past few decades, there has been accumulating evidence that prenatal exposure to risk is negatively related to child self-regulation. However, the mechanisms underlying this relationship are unclear. The present study used a multimethod approach to simultaneously examine the mediating role of the developmental trajectories of observed parenting quality (support, stimulation, and structure) and children's functional brain networks (small-worldness) from infancy into the preschool period in a sample of 233 children and their biological mothers. The results revealed a potential sleeper effect: Prenatal exposure to risk was negatively related to child self-regulation during the preschool period, but not during infancy. Parenting quality remained relatively stable over time, whereas small-worldness showed an increase during infancy, followed by a decrease into the preschool age period. These developmental changes did not mediate the relation between prenatal risk and child self-regulation. Prenatal exposure to risk was related to lower levels of maternal support during infancy, but did not affect the development of parenting quality over time. Prenatal risk was also not related to the growth rate of small-worldness in young children. However, the developmental changes in small-worldness predicted individual differences in child self-regulation. These findings suggest that children generally have the potential to benefit from positive postnatal parenting environments, regardless of the levels of prenatal risk. A potential target for intervention efforts based on the current findings might be related to postnatal experiences that impact the development of functional brain networks, which in turn could affect the development of child self-regulation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Infection with Plasmodium falciparum enhances extracellular vesicle (EV) production in parasitized red blood cells (pRBCs), an important mechanism for parasite-to-parasite communication during the asexual intraerythrocytic life cycle. The endosomal sorting complex required for transport (ESCRT), and in particular the ESCRT-III sub-complex, participates in the formation of EVs in higher eukaryotes. However, RBCs have lost the majority of their organelles through the maturation process, including an important reduction in their vesicular network. Therefore, the mechanism of EV production in P. falciparum-infected RBCs remains to be elucidated. Here we demonstrate that P. falciparum possesses a functional ESCRT-III machinery activated by an alternative recruitment pathway involving the action of PfBro1 and PfVps32/PfVps60 proteins. Additionally, multivesicular body formation and membrane shedding, both reported mechanisms of EV production, were reconstituted in the membrane model of giant unilamellar vesicles using the purified recombinant proteins. Moreover, the presence of PfVps32, PfVps60 and PfBro1 in EVs purified from a pRBC culture was confirmed by super-resolution microscopy and dot blot assays. Finally, disruption of the PfVps60 gene led to a reduction in the number of the produced EVs in the KO strain and affected the distribution of other ESCRT-III components. Overall, our results increase the knowledge on the underlying molecular mechanisms during malaria pathogenesis and demonstrate that ESCRT-III P. falciparum proteins participate in EV production., Competing Interests: The authors have declared that no competing interests exist.

Objective: Borderline personality disorder affects up to 2% of the population and is associated with poor functioning, low quality of life and increased mortality. Psychotherapy is the treatment of choice, but it is unclear whether specialized psychotherapies (dialectical behavior therapy, mentalization-based treatment, transference-focused therapy and schema therapy) are more effective than non-specialized approaches (e.g. protocolized psychological treatment, general psychiatric management). The aim of this systematic review is to investigate the effectiveness of these psychotherapies., Methods: PubMed, PsycINFO, CINAHL, EMBASE and CENTRAL were searched from inception to November 2017. Included randomized controlled trials were assessed on risk of bias and outcomes were meta-analyzed. Confidence in the results was assessed using the Grading of Recommendations Assessment, Development and Evaluation method. The review has been reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines., Results: A total of 20 studies with 1375 participants were included. Specialized psychotherapies, when compared to treatment as usual or community treatment by experts, were associated with a medium effect based on moderate quality evidence on overall borderline personality disorder severity (standardized mean difference = -0.59 [95% confidence interval: -0.90, -0.28]), and dialectical behavior therapy, when compared to treatment as usual, with a small to medium effect on self-injury (standardized mean difference = -0.40 [95% confidence interval: -0.66, -0.13]). Other effect estimates were often inconclusive, mostly due to imprecision., Conclusion: There is moderate quality evidence that specialized psychotherapies are effective in reducing overall borderline personality disorder severity. However, further research should identify which patient groups profit most of the specialized therapies.